.div_header_wh {
  width:900px; margin-left:auto; margin-right:auto;
}
.div_menu_wrapper {
  background:lightblue;
}
.div_menu_wh {
  width:900px; margin-left:auto; margin-right:auto;
}
.div_page_wh {
  width:900px; margin-left:auto; margin-right:auto;
}
.div_footer_wh {
  width:900px; margin-left:auto; margin-right:auto;
}